Anthracyclinones. Part 5. Synthesis of some anthracyclinones and 4-hydroxyanthracyclinones containing a tertiary methyl carbinol function in ring A from D-glucose precursors

Deoxygenation of tertiary and secondary alcohols ROH by thiol-catalysed radical-chain redox decomposition of derivatives ROCH2X to give RH and XCHO

“…2-Methyladamantan-2-ol was obtained commercially (Aldrich). 1,1-Dicyclohexylethanol 18 and 1,2:5,6-diisopropylidene-3-C-methyl-α--allofuranose 19 were prepared according to literature methods from the appropriate ketones and methylmagnesium iodide. 1-Methylcyclododecanol 20 was prepared in a similar way from cyclododecanone and showed mp 91-92 ЊC (lit., 20 91-92.5 ЊC); δ H 1.17 3β-Methylcholestan-3α-ol 21 was obtained as a mixture with the 3α-epimer from the reaction of methylmagnesium iodide with cholestan-3-one.…”

Radical-chain deoxygenation of tertiary alcohols, protected as their methoxymethyl (MOM) ethers, using thiols as polarity-reversal catalysts

“…( 4)]. Swern oxidation followed by treatment of the derived ketone with methylmagnesium iodide afforded the tertiary alcohol 5, 7 which was converted to the corresponding MOM ether 6. The latter was heated under reflux in octane in the presence of TBST (3 3 3 mol%), DBPB (3 3 10 mol%), to afford, after chromatography, a 91:9 mixture of 4 9 and its C-3 epimer in a total isolated yield of 90%.…”